Here goes: I started modifying Atton Rand to turn him into a Twi'lek. I changed his head to Head 65 (orange twi'lek), and modified P_AttonBA.tpc and P_AttonBAD01.tpc to change what I thought was hand texture to orange.

However, in game, Atton still retains his Caucasian human hands but with a Twi'lek head. Am I modifying the wrong files?

You also need to edit the P_Atton.tpc file and change the hands to orange